I transferred my itunes software from a laptop to a desktop because I now want to use the desktop to sync my ipod touch. The transfer went okay and but I found I could not sync about 40 songs I had on my laptop. The songs appeared with exclamation points indicating the software could not find the paths to the music files. So I located the 40 music files on the laptop and transferred and added them to the desktops itunes program. After loading the 40 missing files, the problem was solved for a few minutes..I tried the songs and they payed, but about five minutes later, the same music files disappeared again! What's causing this frustrating problem??